Respiratory System: Functions, Organization, and Mechanics of Respiration

Question 1

What is the most critical function of the respiratory system?

Answer 1

provide oxygen (deliver of oxygen to the cells is a multi-step process

Question 2

CO2 is an ___ waste product. Draw the equation of turning CO2 into bicarb.

Answer 2

acidic

CO2 + H2O → H2CO3- → HCO3- + H+

Question 3

How does the respiratory system regulate blood pH?

Answer 3

ventilation rate affects the amount of CO2 in plasma

Question 4

The respiratory systems facilitates speech via the ___ ___.

Answer 4

vocal cords

Question 5

What are the three mechanisms used to provide microbial defense?

Answer 5

1. epithelial secretions
2. lymphoid tissue in tract
3. coughing and sneezing reflexes

Question 6

Epithelial secretions are ___ that traps stuff. Lymphoid tissues are found in the wall of respiratory passages and prevent pathogens from entering the ___. ___ and ___ help to expel irritants deep in respiratory tract or nasal passages.

Answer 6

mucus; blood; coughing; sneezing

Question 7

___, an enzyme found in the endothelial cells of the lung, convert angiotensin I to angiotensin II.

Answer 7

ACE

Question 8

How does the respiratory system defend against small blood clots that get trapped in the narrow vessels of the lungs?

Answer 8

they are dissolved because there is a high concentration of fibrolysins in the lungs.

Question 9

T/F. Airways are the site of gas exchange between air and blood and the lungs are a series of tubes needed to exchange air between lungs and environment.

Answer 9

False, LUNGS are the site of gas exchange between air and blood and the AIRWAYS are a series of tubes needed to exchange air between lungs and environment.

Question 10

What mechanical aids are used to vary the volume of the thoracic cavity?

Answer 10

skeletal muscles

Question 11

The upper airway structures are ___ (inside/outside) of the thoracic cavity. List those structures?

Answer 11

outside

mouth/nose → pharynx → larynx→ top of trachea

Question 12

The conducting zones can be found in the ___ cavity but no ___ ___ occurs.

Answer 12

thoracic; gas exchange

Question 13

List the structures found in the conducting zone.

Answer 13

trachea → primary bronchi → secondary bronchi → bronchioles → terminal bronchioles

Question 14

The trachea and bronchi include ___ rings and ___ glands, but the bronchioles lose ___ and ___ and add ___ ___.

Answer 14

cartilaginous; mucous; cartilage; glands; smooth muscle

Question 15

In what structures does gas exchange occur?

Answer 15

Respiratory zone

respiratory bronchioles → alveolar ducts → alveolar sacs

Question 16

___ bronchioles are very ___-walled and contain ___ in their walls.

Answer 16

Respiratory; thin; alveoli

Question 17

In branching, 1 tube → ___ million tubes → ~300 ___ alveoli.

Answer 17

8; million

Question 18

Branching creates ___ airways to maintain airflow and minimize increasing ___ to airflow.

Answer 18

parallel; resistance

Question 19

When air is warmed and moistened, what is exchanged with the blood in airway walls?

Answer 19

heat and water vapor

Question 20

How does the conducting zones protect against microbes?

Answer 20

1. goblet cells secrete mucus which can trap airborne particles and pathogens
2. cilia on epithelial cells move mucus upwards to the pharynx where it can be swallowed or expelled

Question 21

What cells does smoking damage?

Answer 21

epithelial cells so an individual must cough to clear passages.

Question 22

Cystic fibrosis is a disease the impairs the normal functioning of which zone?

Answer 22

conducting

Question 23

In cystic fibrosis, a mutation in the genetic code for ___ channels reduces the amount of ___ and ___ secreted across the epithelium into the mucus.

Answer 23

Cl-; Na+; Cl-

Question 24

What is the consequence of having less water in the mucus (due to osmosis) of cystic fibrosis patients?

Answer 24

their mucus, which is thick and dry, traps infectious agents, is not expelled and obstructs the airway

Question 25

What regulates airflow in the respiratory zone?

Answer 25

bronchiolar smooth muscles that have the ability to dilate and constrict (regulated by autonomics)

Question 26

Why are alveoli well-suited for optimizing gas exchange?

Answer 26

1. high surface area for increased gas diffusion
2. highly vascularized
3. respiratory surface very thin
4. low rate of blood flow provides time for exchange

Question 27

Microbial defense is provided by pulmonary ___.

Answer 27

macrophages

Question 28

Match the following cells of the alveoli with their function:

A. Type I
B. Type II
C. Macrophages

1. secrete surfactant
2. immune cells
3. epithelial; gas exchange surface

Answer 28

A - 3
B - 1
C - 2

Question 29

What is the most important factor for alveoli and pulmonary capillaries?

Answer 29

thinness

Alveolar sacs are ~0.5um in diameter
Distance between alveolus and capillary ~0.2um

Question 30

Respiratory gases are small ___ molecules that diffuse down a “___” gradient easily through plasma ___ but less easily through body ___.

Answer 30

nonpolar; concentration; membranes; fluids

Question 31

What are the rates of diffusion for O2 and CO2? Why are they different?

Answer 31

They are different due to their different solubilities

CO2 solubility = 77mmol/L
O2 solubility = 2.2mmol/L

Question 32

From the air, what layers must O2 cross to enter the plasma?

Answer 32

air in alveolus → across apical membrane of Type I cell → through cytoplasm → across basal membrane of Type I cell → across basal lamina and underlying connective tissue → across basal membrane of endothelial cell → through cytoplasm → across apical membrane of endothelial cell → in plamsa

Question 33

O2 must diffuse/move in reverse to leave blood in ___ capillaries and be delivered to ___ in tissues.

Answer 33

systemic; mitochondria

Question 34

What are the skeletal and muscular elements that enclose the lungs inside the thoracic cage?

Answer 34

spinal column, ribs, breastbone (sternum), neck muscles, diaphragm and intercostal muscles

Question 35

Each lungs is surrounded by a pleural sac. What are the two layers of this sac?

Answer 35

1. parietal (outer) pleura - adheres to the underside of the thoracic wall and the top of the diaphragm
2. visceral (inner) pleura - covers the outer surface of the lung

Question 36

The ___ fluid surround the lungs and ___ the pleural surfaces so that they can slide over each other during breathing.

Answer 36

intrapleural; lubricates

Question 37

How thick is the intrapleural fluid that fills the sacs? What happens to the intrapleural fluid when the thoracic cage expands or contracts?

Answer 37

10 - 20um thick

subject to pressure changes when thoracic cage expands or contracts

Question 38

___ is required to bring freshly oxygenated air into the lungs and ___ relies on pressure differences between the air in the lungs and the air outside of the lungs.

Answer 38

Ventilation; ventilation

Question 39

Define airflow.

Answer 39

a function of the pressure gradient and the resistance to flow within the airways

F = change in P / R or F = (Palv - Patm) / R

Question 40

Patm = pressure at ___ level = ___mm Hg or ___ atm

Answer 40

sea; 760; 1 (for this class Patm = 0

Question 41

What happens if Palv is less than Patm?

Answer 41

If Patm is = 0, then Palv is negative and air flows into lungs (inspiration)

Question 42

T/F. If Palv is greater than Patm then air flow out of lungs (expiration).

Answer 42

True.

Question 43

Alveolar pressure changes in response to changing the volume of the lungs according to Boyle’s law. What is Boyle’s law?

Answer 43

P1V1 = P2V2

Question 44

What three pressures relate to ventilation?

Answer 44

1. alveolar (Palv) - air pressure w/in alveoli
2. Intrapleural (Pip) - pressure of fluid in the intrapleural space
3. transpulmonary (Ptp)

Question 45

How do you determine the transpulmonary pressure?

Answer 45

Ptp = Palv - Pip

Question 46

During inspiration, the ___ contracts and lowers the floor of the cavity to ___ volume. The ___ intercostal muscles contract and raise the ribcage to ___ the volume.

Answer 46

diaphragm; increase; external; increase

Question 47

During expiration, the ___ relaxes and raises the floor of the cavity to ___ volume and ___ intercostals relax to lower the ribcage and ___ volume.

Answer 47

diaphragm; reduces; external; reduces

Question 48

As the volume of the thoracic cavity expands during inspiration, what happens to Pip, Ptp and Palv?

Answer 48

Pip decreases and Ptp becomes more positive as a result and the lungs expand (increase vol of alveoli). As this occurs, Palv becomes more negative compared to Patm and air flows inward.

Question 49

T/F. Between breaths, Patm is negative and Palv is greater causing one to exhale.

Answer 49

False, during breaths, Patm is = 0; Palv = Patm between breaths (so NO air is moving)

Question 50

The ___ tend to recoil inward and the ___ ___ tends to recoil outward.

Answer 50

lungs; chest wall

Question 51

T/F. Between breaths, Pip is always subatmospheric.

Answer 51

True.

Question 52

What muscles are involved in forced inspiration? expiration?

Answer 52

forced inspiration:

• SCM
• pectoral ms
• scapular ms

forced expiration:

• abdominal ms
• latissimus dorsi
• internal intercostal ms

Question 53

When the diaphragm and inspiratory intercostals contract, the thorax ___ and ___ becomes more subatmospheric. There is an ___ in transpulmonary pressure and the lungs ___. Palv becomes ___ and air flows ___ the alveoli.

Answer 53

expands; Pip; increase; expand; subatmospheric; into

Question 54

When the diaphragm and inspiratory intercostals stop contracting, the chest wall ___ and ___ moves back toward its preinspiratory value. ___ pressure moves back also and the lungs ___ toward their preinspiratory size. Air in the alveoli becomes ___ and Palv becomes ___ than Patm so air flows ___ of the lungs.

Answer 54

recoils; Pip; Transpulmonary; recoil; compressed; greater; out

Question 55

A ___ occurs when the lung (actually the ___ ___) is punctured. ___ air enters the intrapleural space and the intrapleural pressure increases to ___. Now Pip is equal to Patm. The pressure acting to hold the lung open is thus eliminated and the lung ___. At the same time the chest wall moves ___ because the elastic recoil is no longer opposed.

Answer 55

Pneumothorax; pleural sac; Atmospheric; zero; collapses; outward